Wagon-jack.



PATBNTED AUG. 25, 1903.

E. PRESCOTT, WAGON JACK.

APPLIOATION FILED MAR. 16, 1903- I N0 MODEL.

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UNITED STATES i Patented August 25, 1903.

PATENT OFFIoE.

EDWIN PRESCOTT, OF ARLINGTON, MASSACHUSETTS.

WAGON -JACK.

SPECIFICATION forming part of Letters Patent No. 737,016, dated August25, 1903.

Application filed March 16, 1903.

To all whom it may concern:

Be it known that I, EDWIN Pansoorr, a citizen of the United States,residing at Arlington, in the county of Middlesex and State ofMassachusetts, have invented an Improvement in Wagon-Jacks, of which thefollowing description, in connection with the accompanyin g drawings, isa specification, like letters on the drawings representingv like parts.

My invention aims to provide an improved wagon jack, the invention beingdirected more particularly to the end of providing a jack which willwithstand the rough usage to which wagon-jacks are subjected moreeffectually than any jack of its type heretofore made and one which alsowill preserve substantially the original distribution of bearing pointsand stresses notwithstanding the wear of the various parts.

My invention will be best understood from a description of oneembodiment thereof in connection. with theaccompanying drawings,wherein-- Figure 1 in side elevation shows a jack illustrating oneembodiment of my invention, the full lines showing the parts whensustaining a weight, the dotted lines showing the positions of the partswhen the handle is raised to release the jack. Fig. 2 is an edge view ofFig. 1 to show the ear-protection ribs; and Fig. 3 is a cross-section onthe dotted lines 3 3, Fig. 1, looking downward.

. In the particular embodiment of my invention selected for illustrationherein and shown in the drawings, a is the base of suitable shape uponwhich is arranged the stand orpostb,both of which may be made of wood.The stepped head 0, preferably ofiron,is mounted upon the upper end of ahead-supporting bar d, which is connected with the post b by parallellinks 6, so that the said post and its head may be raised and loweredwhile preserving the same vertical alinement. For raising and loweringthe stepped head with any weight thereon I have provided the handle f,which at its innor end enters a socket or recess provided thereforbetween the rearwardly-extended ears 0 on the head, said handle beingpivotally secured to and between said ears by a bolt 0 Said handle atthe same end and near the pivot-bolt c has jointed to it by abolt f apair of links f which straddle the Serial No. 1 17,9307. (No model.)

said handle and also. the post I) and are pivotally connected to thelatter by a bolt f 'When the handle is raised to its dotted position,Fig. 1, the head drops to its lowermost position, in which it rests withthe lower end of its carrying'bar cl upon the base. When the handle isturned downwardly into its fullline position,Fig. 1, the handle-bolt fat the upper ends of the links f serves as a moving fulcrum about whichthe head, with any object resting thereupon, is raised to its full-lineposition, Fig. 1. In this swinging movement the handle-bolt f is carriedinwardly beneath the head-bolt c and beyond the vertical or dead-centerline between said head-bolt and the bottom link-boltf upon thepost untilit is arrested by contact of the sides of the links with thestop-surfaces 0 provided therefor on the head. In this position theweight resting upon the stepped head is sustained in an almost directline by the head-bolt c handle, handle-boltf, links f and the link boltfand the greater the weight the more firmly is the handle-bolt j pressedto the left with the sides of its links bearing against the stopsurfaces0 In jacks of this general type as heretofore made it has been common torely upon the contact of the handle-lever itselfwith the top corner ofthe post I) to limit the swinging movement of the handle-pivot beyondthe vertical or dead-center line between the head bolt and the lowerlink-bolt. The objection to this construction has been that the contactof wood to wood soon wears sufficiently to permit the handle-boltf topass to a greater extent beyond the Vertical dead-center line betweenthe head-bolt and lower link-bolt, thus increasing the buckling tendencyof the toggle and rendering the entire construction more susceptible tobreakage. By my invention, wherein the movement of the handlebolt ortoggle past the dead-center line referred to is limited by contact ofthe metal links themselves with the metal head, there is no suchappreciable wear as if the contacting members were of wood, and itmatters not how much the bearing-surfaces between the handle-boltf andthe upper ends of the links may wear the points of contact between thesides of the link and the head remain constant, so that regardless ofwear between the bearing-surfaces of the various joints the arrangementof lines of pressure or support remain substantially constant throughoutthe life of the jack. A clearance 75 is provided between the tops of thelinks and the portions of the head immediately overlying the same toprevent the ends of the links upon wearing of the bearing-surfacesthereat from coming into contact with the said head, which would bedetrimental, as it would transfer the sustained weight directly to theends of the links without first passing through the head-bolt 0 which isnecessary to maintain the toggle-lock.

In jacks of this type it is desirable that the upper ends of the linksbe carried under the portion of the head to which the handle-lever ispivoted, and it is also desirable that the handle-lever itself beengaged between projecting portions or cars upon the said head, asherein shown. These ears I have found in practice are perhaps moreeasily broken than any other part of the jack, for when the latter istipped or thrown upon its side, as frequently occurs in the ordinaryhandling thereof, or when a wheel rolls over the jack when lying flatupon the floorthese ears, one or both, have been found in practice tobe, as a rule, the first to break, the fracture usually occurringthrough the bolt-holes. To prevent this so far as possible, my inventioncontemplates providing the head with lateral protecting ribs or wings,herein indicated at g, which begin some distance below the ears at therear edge of the head and gradually increase in extent of width orheight to a point preferably immediately adjacent to the lowerboundaries of the said ears and then taper off quickly to nothing at orabout the level of the head-bolt 0 When a jack so constructed is tippedor thrown upon its side, these protection ribs or wings first strike thefloor and receive the impact, thus preventing the bolt-head, nut, or thetips of the ears themselves or other easilybreakable part fromcontacting with the floor to the damage thereof. Obviously theprotection-wings are well calculated to withstand the shock of a fall,because they are supported by the body of the head itself and receivethe blow in the direction of their greatest depth, down through thesolid metal of the body, and not laterally, as would the ears.

My invention provides a jack which without additional cost willwithstand much longer and severer usage than any jack of its typeheretofore known to me without breakage, without appreciable change inthe lifting or looking movements, and without disor moreprotection-flanges adjacent said ears or one of them.

2. A lifting-jack of the type described provided with a movable headhaving rearwardlyextended cars, a lifting-handle pivoted to and betweensaid ears, and oppositely-extended protection-wings on and adjacent therear edge of said head and having their highest points adjacent thelower meeting points of the said ears with the said head.

3. A lifting-jack of the type described provided with a head, alifting-handle, and one or more handle-supporting links, said parts soarranged that the links alone contact laterally with the head when insupporting position.

t. A lifting-jack of the type described provided with a head, alifting-handle jointed thereto, one or more handle-supporting linksjointed to said handle and arranged to form in connection with thelatter a self-locking toggle when the head is in supporting position,said head and supporting link or links being constructed and arranged toprovide a wear-space between the end or ends of said link or links andthe adjacent portion of the said head, whereby to prevent contact of thesaid link or links at the end or ends thereof with said head upon wearof the said joints or any of them, thereby preserving throughout thelife of the jack substantially the original lines of locking support.

5. A lifting-jack of the type described, provided with a head, alifting-handle, and one or more handle supporting links formingtherewith a lifting 'and supporting toggle for said head, said links bylateral contact with said head furnishing the sole lateral support forsaid toggle when in supporting position.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

EDWIN PRESCOTT.

Witnesses:

FREDERICK L. EME Y, EVERETT S. EMERV.

ITO

